Non-volatile counters are used in a variety of position detection applications for counting pulses from a sensor. For example, flowmeters can include rotating components with magnetic elements and sensors to detect a rotating magnet passing a fixed point. A counter provides a counter value representing the number of detected magnetic pulses, and hence, the amount of liquid flow through the meter. Other position sensor applications include elevator pulley systems with rotating components that provide changing magnetic fields that can be sensed by magnetic sensors. Some counter systems count pulses from two or more sensors and selectively determine whether the counter value should be incremented or decremented based on the sensor pulse signals. Non-volatile pulse counter systems are useful in a variety of situations in which power is lost but the position of a rotating or moving structure is needed. For example, utility meters are used to assess the amount of water used by customers for billing purposes. Electrically powered flowmeters can be used to provide a counter value representing the amount of water used by a particular customer. It is desirable to update the counter value to account for water usage even when external power is unavailable. In another example, automated rotating tools or machinery can be manually rotated while power is removed. Non-volatile pulse counter systems use energy harvested from the rotation of the system components in order to operate the counter for incrementing or decrementing as appropriate. This allows the system, upon power up, to know the position of the movable parts and operate accordingly. In another example, elevator transport systems can undergo power loss while in motion, and the momentum of the elevator causes a position change even after power is removed. Non-volatile counter systems allow a counter value to be updated even while external power is unavailable in order to correctly indicate the position of the elevator when power is restored. For certain applications such as flow meters and rotary encoders, the position sensors need to be compact, and the use of small, low cost energy harvesting sources is beneficial. However, the energy available for harvesting to power a non-volatile counter is restricted when system power is unavailable.